Port Jefferson (NY) monthly weather averages

Contents

Average daytime temperature

The bar chart below shows the average monthly peak daytime temperatures at Port Jefferson

Port Jefferson average temperature chart (Celsius) Port Jefferson average temperature chart (Fahrenheit)
Average monthly temperatures in Port Jefferson (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 2.9 3.8 8.6 14.5 20 24.8 27.6 26.8 23.3 17.7 11.9 5.8
°F 37.2 38.9 47.5 58.1 68.1 76.6 81.7 80.3 73.9 63.9 53.5 42.5

Please note: these are the average peak daytime temperatures (usually around mid-afternoon) so do not show daytime / night highs and lows. To see the daily range of temperatures have a look at the temperature max / min chart below.

Average rainfall & rainy days

The graph below shows the average rainfall and number of rainy days per month.

Port Jefferson monthly rainfall chart (mm) Port Jefferson monthly rainfall chart (inches)
Average monthly rainfall in Port Jefferson (mm and inches)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
mm 92 84 107 104 96 88 88 99 89 90 107 106
inches 3.6 3.3 4.2 4.1 3.8 3.5 3.5 3.9 3.5 3.5 4.2 4.2
Rainy days 10 10 11 10 11 10 9 9 8 7 11 11

Average annual rainfall in Port Jefferson: 1119.334mm (440.7 inches)

Average daily sunshine

The bar chart below shows the average daily sunshine hours in Port Jefferson

Port Jefferson average daily sunshine chart
Average daily sunshine Port Jefferson
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Hrs sunshine 6.1 6.9 7.8 8.5 9 9.5 9.4 9.1 8 7.4 5.5 5.1

Day / night temperatures

The graph below shows the daily range of temperatures for each month.

Port Jefferson average minimum / maximum temperatures (Celsius) Port Jefferson average minimum / maximum temperatures (Fahrenheit)
Maximum and minimum daily temperatures in Port Jefferson (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C -4.9 -4.5 -0.5 4.1 9.3 14.6 18 17.8 14.1 8.5 3.7 -1.8
Max °C 3.1 4.1 8.9 14.8 20.3 25.1 27.9 27.1 23.5 18 12.2 6
Min °F 23.2 24 31.2 39.3 48.7 58.2 64.3 64 57.4 47.2 38.6 28.8
Max °F 30.4 31.6 39.6 48.9 58.6 67.6 73.2 72.3 65.8 55.8 46.2 35.8

Sea temperature

The graph below shows the average sea temperature.

Port Jefferson average sea temperature chart (Celsius) Port Jefferson average sea temperature chart (Fahrenheit)
Average sea temperature around Port Jefferson in degrees centigrade and fahrenheit
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 6.8 4.9 4.8 6.9 11.2 17 21.8 22.8 20.6 16.8 12.9 9.6
°F 44.2 40.8 40.6 44.4 52.2 62.5 71.3 73 69.1 62.3 55.2 49.2

Wind speed

The graph below shows the average wind speed.

Port Jefferson average winspeed by month (km/h) Port Jefferson average winspeed by month (mph)
Average wind speed in Port Jefferson (mph and kmh)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
km/h 20 21 21 20 18 17 16 16 17 17 19 20
mph 13 13 13 12 11 10 10 10 10 11 12 12

A monthly average windspeed of over 16km/h or 10mph suggests a location is fairly windy.

Relative humidity

The graph below shows the average relative humidity.

Port Jefferson relative humidity averages
Average relative humidity in Port Jefferson
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
68% 67% 65% 64% 70% 73% 73% 75% 75% 72% 70% 69%

Other monthly averages

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Beta

Current (hourly) weather 15 day forecast

Port Jefferson weather stats

Port Jefferson weather statistics
Hottest month: July 27.6°C 81.7°F
Driest month: February 84mm 3.3ins
Sunniest month: August 9.1hrs
Coldest month: January 2.9°C 37.2°F
Wettest month: November 107mm 4.2ins
Warmest sea: August 22.8°C 73°F
Map showing location of Port Jefferson (40.94649, -73.06927) Port Jefferson map pin © Google

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